Connector for fractured tubular bones

ABSTRACT

An elongated rod-shaped element can be inserted into the curved longitudinal cavity of a fractured tubular bone. At its front end it is provided with an expander portion by means of which it can expand an expansion element provided at the front end of a tubular sleeve which surrounds the rod, when the latter is moved axially and rearwardly with respect to the front end of the tubular sleeve. The expander portion may be releasably connected with the rod for which purpose inter-engaging coupling portions may be provided on the rod and on the expander portion.

mired States Patent Fischer et a1.

[451 ept. r, 1973 CONNECTOR FOR FRACTURED TUBULAR BONES [75] Inventors:Artur Fischer, Altheimei Strasse 219, Tumlingen, Germany; Jean-NicolasMuller, Strassburg, France [73] Assignee: said Fischer, by said Muller[22] Filed: Mar. 13, 1972 [21] Appl. No.: 234,097

[30] Foreign Application Priority Data Mar. 13,1971 Germany P 21 12138.0

[52] US. Cl. 128/92 BC {51] Int. Cl. A61115/04 [58] Field of Search128/92 BC, 92 BB, 128/92 R, 92 CA, 92 B, 92 D; 85/77, 84

[56] References Cited UNITED STATES PATENTS 2,699,774 1/1955 Livingston128/92 BB 2,490,364 12/1949 Livingston 128/92 BB 2,381,050 8/1945Hardinge 128/92 BB 3,678,925 7/1972 Fischer et al. 128/92 BB 2,243,7175/1941 Moreira 128/92 BB 2,121,193 6/1938 3,332,312 7/1967 3,254,5556/1966 3,512,448 5/1970 Summerlin et a1 85/77 FOREIGN PATENTS ORAPPLICATIONS 453,570 6/1968 Switzerland 128/92 BC PrimaryExaminerRichard A. Gaudet Assistant Examiner.l. Yasko Altorney-MichaelS. Striker [57] ABSTRACT An elongated rod-shaped element can be insertedinto the curved longitudinal cavity of a fractured tubular bone. At itsfront end it is provided with an expander portion by means of which itcan expand an expansion element provided at the front end of a tubularsleeve which surrounds the rod, when the latter is moved axially andrearwardly with respect to the front end of the tubular sleeve. Theexpander portion may be releasably connected with the rod for whichpurpose interengaging coupling portions may be provided on the rod andon the expander portion.

9 Claims, 4 Drawing Figures CONNECTOR FOR FRACTURED TUBULAR BONESBACKGROUND OF THE INVENTION The present invention relates generally to amedical appliance and more particularly to a connector for fracturedtubular bones.

Connectors for fractured bones are known, and it is known to useconnectors having expansible elements for anchoring in a hole which isdrilled into the bone fragments which are to be reunited. If, however,tubular bones are fractured which have a longitudinally extending curvedinterior cavity which is filled with bone marrow it was until recentlyunknown to use that type of connector; instead these bone fractures werealways repaired by driving pins into the fragments of the bone.

The state of the art was advanced in this respect with our proposal in aco-pending application Ser. No. 227,371 filed in our names on Feb. 18,1972, under the title Supporting Device for Fractured Tubular Bones,wherein there is proposed a sleeve-shaped support element into which arod-shaped expander element is inserted. The support element is curvedin a manner which is at least substantially the same as the curvature ofthe interior cavity of the tubular bone, and when inserted into thiscavity via an opening drilled into the bone for this purpose in order toafford access to the cavity, the support element is in contact with thewall surface bounding the bone marrow cavity over a relatively largesurface area, due to its curvature corresponding to that of the cavityitself. With this device the fragment of the bone are secured againstlateral displacement and cannot shift relative to one another at thefracture line. Because of this, callus may be formed in a very brieftime at the fracture line, thus reuniting the bone fragments.

The device in the aforementioned copending application can be anchoredby means of an expansible portion in the bone fragments, permitting amuch earlier application of loads to the bone than was possible with theprevious practice of driving pins into the bones. Furthermore, the factthat the support element can be so anchored serves, of course, toeliminate the need for the use of wires or pins which might otherwisehave to be driven into the bone from the side in order to secure thesupport element against shifting or twisting in the cavity, and theoverall effect observed with the construction set forth in theabove-mentioned application is a significant reduction in thehospitalization time of a patient whose fracture has been repaired withthe aforementioned device.

However, it has also been observed that even this significantly improveddevice does not meet all require ments as yet. The support deviceaccording to the aforementioned application can be readily inserted intothe cavity of the tubular bone when the bone fragments are either not oronly slightly displaced relative to one another in lateral direction atthe fracture line. However, if such displacement has occurred and is ofa more than slight nature, then the fact that the outer diameter of thesleeve-shaped support element is adapted to the inside diameter of thebone marrow cavity wouls result, when the device is driven into thecavity in contact with the laterally displaced downstream bone fragment,that is the fragment which the device would encounter only after it hasbeen driven into the first fragment, in desctruction of this downstreambone fragment beyond the fracture line.

SUMMARY OF THE INVENTION Accordingly, it is a general object of thepresent invention to provide a device or connector of the type hereunder discussion which is a further improvement over what is known fromthe aforementioned application and which avoids the disadvantages justoutlined.

More particularly it is an object of the present invention to provide animproved supporting device for fractured tubular bones having alongitudinally extending interior cavity.

An additional object of the present invention is to provide such adevice which permits preliminary fixation of the bone fragments in theircorrect relative position before the supporting sleeve of the device isinserted into the bone marrow cavity, and which permits holding them inthis position until the supporting sleeve has been so inserted.

In pursuance of these objects and of others which will become apparenthereafter, one feature of the invention resides, briefly stated, in asupporting device for fractured tubular bones having a longitudinallyextending interior cavity which device comprises an elongated rod-shapedelement adapted to be inserted with clearance into the cavity and havinga trailing end portion and a leading end portion. An expander element isprovided on the leading end portion and an elongated supporting tube isprovided, being dimensioned to fit over the rod-shaped slement andadapted to be inserted into the cavity by sliding over the rear endportion and onto the rod-shaped element. An expansible element isprovided at the front end of the tube and is dimensioned to abut theexpander element when the tube is slid over the rod-shaped element.Moving means is also provided for the purpose of moving the rod-shapedelement in the tube axially of the same and rearwardly away from thefront end of the tube whereby the expander element is drawn into andthereby expands the expansible element.

Another concept according to the present invention proposes to achievethe aforementioned objects by utilizing a supporting device having anelongated curved supporting tube element adapted for insertion into thecavity longitudinally thereof and having a leading end portion. Anexpansible element is provided on the leading end portion and anexpander element is also provided for expanding the expansible element.A red shaped element is receivable in the tube element and has a frontportion, a rear portion and an intermediate portion of which at leastthe latter has a cross'section so dimensioned as to permit angulardisplacement of the rod-shaped element in the tube element. Cooperatingcoupling portions are provided on the expander element and the frontportion of the rod-shaped element in order to effect coupling of theexpander element to the rod-shaped element in response to angulardisplacement of the latter. Moving means is again provided which movesthe rod-shaped element in the tube rearwardly of the leading end portionso as to effect expansion of the expansion element with the expanderelement when the latter is connected with the rod-shaped element.

When the device is constructed in accordance with the first-mentionedconcept of the invention, the rodshaped element in fact serves as a pinpermitting the preliminary fixation of the bone fragments relative toone another. The fractured tubular bone is first pro vided with a holein the region of its bulge, so as to gain access to the bone marrowcavity. Through this hole, provided in conventional manner with a drillor the like, is inserted the rod-shaped element which is curved inconformance with the curvature of the bone marrow cavity. The outsidediameter of the rod-shaped element, which is small with respect to thediameter of the bone marrow cavity, makes it possible to insert the rodinto all of the bone fragments without any difficulty, even though arelatively significant lateral displacement of the bone fragmentsrelative to one another at the fracture line may have occurred.

Once the rod-shaped element is so inserted into the bone marrow cavity,the fragments are now aligned in longitudinal direction and held in thisposition. Over the thus inserted rod the similarly curved supportingtube is then pushed into the bone marrow cavity untl the expansibleelement which is provided at the front end of the tube, comes in contactwith the expander element which is provided at the front end of therodshaped element. The moving means is now operated, consistingadvantageously of a cap sleeve which is internally threaded to mesh withexternal thread provided at the rear end of the rod-shaped element, andwhen this is done the rod-shaped element is drawn axially rearwardlyinto the tube so that the expander element expands the expansibleelement on the tube, an choring the entire device in one of the bonefragments.

During the anchoring operation the rod-shaped element moves only inaxial direction of the tube, it being evident that the curvature of thetube and of the rod shaped element will prevent a turning or twisting ofthe latter in the tube. Due to the curvature of the tube, the latter isin contact with the inner wall bounding the bone marrow cavity over arelatively large surface area, whereby an excellent securing of the bonefragments against lateral displacement is obtained. Of course, theanchoring of the device in the bone fragment means that the other bonefragment in which the device is not anchored may be engaged by themoving means or another component provided for this purpose, therebyexerting an axial stress upon the bone fragments in a sense drawing themtogether to prevent their relative axial displacement.

It is advantageous, but not absolutely necessary to provide mating screwthreads on the rod-shaped element and on the expander element, so thatthe latter can be releasably connected with the rod-shaped element; thesame expedient may be used for releasably connecting the expansibleelement to the supporting tube.

As is well known in this field of art, components for devices of thetype under discussion are usually manufactured from VZA or V4A steel,that is material which is not only expensive but can only be shaped andworked with considerable difficulty due to its hardness. Because therod-shaped element can be made separately from the expander element byresorting to the above-mentioned possibility of releasably connectingthem via screw threads, these elements can be manufactured individually,avoiding the necessity for utilizing a large-diameter rod and removingmaterial from it in such a manner as to obtain over most of its length asmall diameter corresponding to the desired diameter for the rod-shapedelement, whereas a remaining portion having the original larger diameterwill constitute the expander element. This is of course a possibility,but due to the difficulty of working the type of steel here in question,of which the components of the device according to the present inventionare advantageously made, the solution of being able to make therod-shaped element and the expander element separately and connectingthem to one another is currently preferred because it is less expensive.

It is also proposed according to the present invention to provide anextension rod which can be threaded into a tapped bore provided in therear endface of the rodshaped element. The extension rod should have adiameter corresponding to that of the rod-shaped element itself, and itis advantageous if its threads provided on its outer surface are alsothe same as those on the rear end of the rod-shaped element and can meshwith the threads of the cap nut which is effectively used for moving therod-shaped element relative to the tube. However, it is also possible toso construct the extension rod that it can be threaded onto the threadsof the rear portion of the rod-shaped element if this is desired, and ineither case, the provision of such an extension permits the surgeon thecomplete insertion of the at least the major portion of the threadedrod-shaped element into the bone marrow cavity without difficulty,whereupon the extension rod can then be removed if desired or necessary.

Insofar as the second embodiment is concerned which was briefly outlinedabove, it should be understood that here again the bone fragments can beprealigned before the device is used to connect them. In this case,however, a conventional pin which in the prior art was used forconnecting such bone fragments to one another, can be inserted into thebone marrow cavity to fix the bone fragments with reference to oneanother against relative displacement. Thereafter the tube is pushedover the pin into the bone marrow cavity, while the bone fragments areheld by the pin against relative displacement. The pin is now withdrawnand the rod-shaped element is inserted into the tube. The rod-shapedelement can be given a small cross section so that it can contact theinner surface of the curved tube over a relatively large surface area.At least the intermediate portion of the rod-shaped element is of suchcross-section or diameter that the rod-shaped element has sufficientflexibility or elasticity to permit it to be angularly displaced in thecurved tube to an extent sufficient to permit engagement of the frontportion of the rod-shaped element with the expander element located atthe front of the tube, in the region of the expansible element.

However, if the rod-shaped element is constructed in this manner, itstorsional strength is not sufficient to permit proper drawing-in of theexpander element into the expansible element. On the other hand, itstensile strength is fully sufficient for this purpose and the inventiontherefore provides for use of a cap nut or sleeve which is engageablewith a rear threaded end portion of the rod-shaped element and which,when turned in requisite sense, will cause the rod-shaped element toperform a movement in the tube which is purely axially of the tube,whereby the rod-shaped element is subjected only to tensile forces indrawing the expander element into the expansible element.

The rod-shaped element may be provided at its front end with couplingportions capable of engagement with similar coupling portions on theexpander element, for instance oppositely located projections which canbe inserted through a corresponding aperture in the expander element andare engageable with the latter after the rod-shaped element performs a90 turn with reference to the expander element. This construction isadvantageous because it requires angular displacement of the rod-shapedelement only through about 90, whereas a threaded connection between therodshaped element and the expander element would require at least two orthree complete turns of the rodshaped element, which would have toresult in the engagement of at least two or three threads on therodshaped element with threads on the expander element in order to takeup the necessary tensile force. Evidently, the possibility outlinedabove is preferable under the circumstances, although the use of threadsis not to be excluded.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an axial section through atubular bone with a device according to the present invention insertedinto it;

FIG. 2 is a fragmentary axial section illustrating a component of thedevice in FIG. 1;

FIG. 3 is a view similar to FIG. 1 illustrating a further embodiment ofthe invention; and

FIG. 4 illustrates another concept of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing the drawing indetail, and firstly referring to FIGS. 1 and 2 thereof, it will be seenthat the device is generally identified with reference numeral 1 and isadvantageously produced in all its components of V2A or V4A steel. Ithas an elongated supporting tube or sleeve 2 to the front end of whichis mounted an expansible element 3 of known construction. In utilizingthis device the bone fragments 12 are first aligned by pushing thethreaded rod-shaped element 5 into the longitudinally extending curvedbone marrow cavity 18, thereby assuring that the bone fragments 12 arealigned in longitudinal direction at the surface of the fracture 13.

Once the rod-shaped element 5 has been so inserted, the tube 2 with theexpansion member 6 accomodated in the expansible element 3 and providedwith an axial passage, is slipped over the rod-shaped element 5 andinserted into the bone marrow cavity 18 until the element 6 contacts theenlargement provided at the front end portion of the element 5.

When, now, the element 5 is shifted in axially rearward direction of thetube 2, for instance by means of an internally threaded cap sleeve 4which is threaded onto the rod-shaped element 5 at the rear end thereof,and is guided in a widened portion 7 at the rear end of the passage ofthe tube 2, the sleeve 4 will bear against a shoulder 3 or else the rearend of the tube 2, so that upon its rotation it will draw the element 5rearwardly with the result that the portion 20 will bear against themember 6, moving the same into the element 3 and causing the latter tospread outwardly and become anchored in the bone marrow cavity.

It is advantageous for the axial length of the member 4 to be socalculated that when the rod-shaped element 5 has been withdrawnrearwardly to the extent necessary to efiect full expansion of theelement 3, its rear end will be sufficiently forwardly spaced from therear end of the member A to permit a cap screw 9 to be threaded intothis rear end, closing it. The cap screw 9 has a head 10 abuttingagainst the annular disc 11.

Projections 14 are provided on the member 6 and guided in slots whichextend longitudinally of the element 3 to prevent relative angulardisplacement of the member 6 and the element 3. The element 3,incidentally, can be threaded into an internal thread 17 provided at thefront end of the sleeve 2 by means of an exterior thread 16 provided onthe element 3.

It will be seen in FIG. 2 that the rod 5 will be constructed fromseveral parts, namely a portion 21 carrying the portion 20 and providedwith an internal thread 22 into which another portion 23 may be threadedby means of an externally threaded part 24. At the rear end the rod 5may be extended by a further portion 25 which is threadedly connectedwith it in the manner illustrated for the purposes outlined earlier.

Coming to the embodiment illustrated in FIG. 3 it will be seen thatthere we have shown a device wherein the tube 2 (it should be noted thatlike reference numerals identify like elements as in FIGS. 1 and 2) canbe pushed over a pin which is temporarily inserted into the bone marrowcavity to provide for temporary and preliminary fixation of the bonefragments 12. In this embodiment the member 6 is located in a recess atthe forward end of the device, being provided with an internal thread30, the root diameter of which is slightly larger than the outsidediameter of the pin which is to be used for the preliminary fixation ofthe bone fragments. Once the pin has been inserted, the tube 2 is pushedover to the maximum extent desired, and thereupon the pin (which is notshown) is withdrawn. Now, the rod-shaped element 5 is inserted into thetube 2 and in this embodiment the element 5 is provided at least in itsintermediate portion of a cross-section so selected that it can beangularly displaced within the tube 2, that is that it is sufficientlyflexible to permit such turning. This is necessary to permit connectionof the member 6 with the element 5. The element 5 may adapt itself tothe curvature of the tube 2 during insertion and during angulardisplacement due to the sufficient elasticity resulting from its smallcross-section at least at the intermediate portion.

The intermediate portion is identified with reference numeral 32 andbounded by a threaded portion 33 to which a cap nut of sleeve shapedconfiguration and identified with reference numeral 34 is to be secured.At the forward end of the rod-shaped element 5 the latter is providedwith a threaded portion 31 which can be threaded into the internalthread 30 of the member 6 as a result of the angular displacement of therodshaped element 5 in the tube 2.

However, as shown in FIG. 4, it is also possible and believed currentlyto be preferable to provide for a different way of connecting the member6 with the element- 5. The forward end portion of the element 5 isprovided with projections, preferably two opposite projections dill,constituting a lacking portion that may be passed through acorresponding aperture 41 provided in member 6 for this purpose. Aftersuch insertion the rod-shaped element is turned through approximately90, whereupon the projections 40 engage the member 6 as illustrated andwhen the rod-shaped element 5 is then drawn axially through the tube 2,the member 6 is taken along to expand the element 3.

Additional recesses are provided at forwardly directed front side of themember 6, being offset through 90 with respect to the aperture 41, sothat the projections 41) can engage in and become locked in theserecesses 42 to thereby assure that the element 5 cannot twist withreference to the member 6, and vice versa.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in aconnector for fractured tubular bones, it is not intended to be limitedto the details shown, since various modifications and structural changesmay be made without departing in any way from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledgereadily adapt it for various applications without omitting features thatfrom the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

We claim:

1. A supporting device for fractured tubular bones having alongitudinally extending interior cavity, comprising an elongatedrod-shaped element adapted to be inserted with clearance into the cavityand having a trailing end portion and a leading end portion; an expanderelement provided on said leading end portion; an elongated supportingtube dimensioned to fit over said rod-shaped element and adapted to beinserted into the cavity by sliding over said rear end portion and ontosaid rod-shaped element; an expansible element; cooperating couplingportions on said expansible element and on the front end of said tubefor releasably connecting said expansible element to said tube so thatsaid expansible element abuts against said expander element when saidtube is slid over said rod-shaped element; and moving means for movingsaid rod-shaped element in said tube axially of the same and rearwardlyaway from said first end so as to draw said expander element into andthereby expand said expansible element.

2. A device as defined in claim 2, wherein said coupling portions aremating screw threads.

3. A device as defined in claim 1, said moving means comprising a nuthaving internal screw threads; and further comprising an extension rodhaving a diameter not exceeding that of said rod-shaped element andconnectable with said trailing end portion of the latter, said extensionrod and said trailing end portion having external screw threads adaptedto mesh with said internal screw threads.

4. A device as defined in claim 1, wherein at least some of saidelements and means are of rust-free steel.

5. A supporting device for fractured tubular bones having alongitudinally extending curved interior cavity, comprising an elongatedcurved supporting tube element adapted for insertion into said cavitylongitudinally thereof and having a leading end portion; an expansibleelement provided on said leading end portion; an expander element forexpanding said expansible element; a rod-shaped element dimensioned tobe receivable in said tube element and having a front portion, a rearportion, and an intermediate portion with at least the latter having across-section dimensioned to permit angular displacement of saidrod-shaped element in said tube element; cooperating coupling portionson said expander element and front portion for efi'ecting coupling ofsaid expander element to said rod-shaped element in response to angulardisplacement of the latter; and moving means for moving said rod-shapedelement in said tube rearwardly 'of said leading end por-- tion so as toeffect expansion of said expansible element with said expander element.

6. A device as defined in claim 5, said expander element having anopening, and said coupling portions being transverse projections on saidfront portion and engaging surfaces in the region of said opening, saidengaging surfaces being engageable with said projections when said frontportion is inserted into said opening and said rod-shaped element isangulariy displaced.

7. A device as defined in claim 45, wherein said pro jections arediametrically opposite one another.

8. A device as defined in claim 7, said expander element being providedin the region of said opening with a pair of diametrally oppositerecesses each bounded in part by one of said engaging surfaces.

9. A device as defined in claim 8, said opening having one end intowhich said front portion is insertable, and an other end bounded by anendface extending transversely to the axis of said opening; and whereinsaid recesses are provided in said endface.

3 i a i *7

1. A supporting device for fractured tubular bones having alongitudinally extending interior cavity, comprising an elongatedrod-shaped element adapted to be inserTed with clearance into the cavityand having a trailing end portion and a leading end portion; an expanderelement provided on said leading end portion; an elongated supportingtube dimensioned to fit over said rod-shaped element and adapted to beinserted into the cavity by sliding over said rear end portion and ontosaid rodshaped element; an expansible element; cooperating couplingportions on said expansible element and on the front end of said tubefor releasably connecting said expansible element to said tube so thatsaid expansible element abuts against said expander element when saidtube is slid over said rod-shaped element; and moving means for movingsaid rod-shaped element in said tube axially of the same and rearwardlyaway from said first end so as to draw said expander element into andthereby expand said expansible element.
 2. A device as defined in claim2, wherein said coupling portions are mating screw threads.
 3. A deviceas defined in claim 1, said moving means comprising a nut havinginternal screw threads; and further comprising an extension rod having adiameter not exceeding that of said rod-shaped element and connectablewith said trailing end portion of the latter, said extension rod andsaid trailing end portion having external screw threads adapted to meshwith said internal screw threads.
 4. A device as defined in claim 1,wherein at least some of said elements and means are of rust-free steel.5. A supporting device for fractured tubular bones having alongitudinally extending curved interior cavity, comprising an elongatedcurved supporting tube element adapted for insertion into said cavitylongitudinally thereof and having a leading end portion; an expansibleelement provided on said leading end portion; an expander element forexpanding said expansible element; a rod-shaped element dimensioned tobe receivable in said tube element and having a front portion, a rearportion, and an intermediate portion with at least the latter having across-section dimensioned to permit angular displacement of saidrod-shaped element in said tube element; cooperating coupling portionson said expander element and front portion for effecting coupling ofsaid expander element to said rod-shaped element in response to angulardisplacement of the latter; and moving means for moving said rod-shapedelement in said tube rearwardly of said leading end portion so as toeffect expansion of said expansible element with said expander element.6. A device as defined in claim 5, said expander element having anopening, and said coupling portions being transverse projections on saidfront portion and engaging surfaces in the region of said opening, saidengaging surfaces being engageable with said projections when said frontportion is inserted into said opening and said rod-shaped element isangularly displaced.
 7. A device as defined in claim 6, wherein saidprojections are diametrically opposite one another.
 8. A device asdefined in claim 7, said expander element being provided in the regionof said opening with a pair of diametrally opposite recesses eachbounded in part by one of said engaging surfaces.
 9. A device as definedin claim 8, said opening having one end into which said front portion isinsertable, and an other end bounded by an endface extendingtransversely to the axis of said opening; and wherein said recesses areprovided in said endface.